2000 mustang gt engine issues

[ddt4436]

I have a 2000 mustang gt with a 2003 romeo motor 5 speed all stock.The guy I bought it from stated that the motor was blown but I was needing some opinions. The car is hesitant to crak and I have to pat the gas vigorously to get it started. Once started, it runs really rough to the point where I have to keep my feet on the gas and has a knocking sound coming from. The sounds increases with engine speed as well. When I mash the gas the car stalls and shuts off completely. I dropped the tank and took out the fuel pump and hot wired it for a couple seconds and it ran fine but I know a pump can still be bad even if it runs. As far as the knocking I'm new to the 4.6 stangs and really don't know which way to go.Someone told me the timing is off but would timing cause that kind of knock? Any help? Please.

 

[trinity_gt]

So you bought it running like this? The guy told you the engine was blown?

It's a 2000 but has a 2003 engine. This suggests to me the previous owner blew the original engine too and replaced it with a junkyard find. If this one has been hurt too I suspect the previous owner didn't leave the car "stock". He probably ran a healthy shot of nitrous in it and hurt both engines, returning it to stock "stock" before selling. Did you scour the car looking for evidence of stuff like mounting bracket holes in the trunk? A hole & grommet to get a nitrous line through? Wiring modifications near the TPS etc?

It sounds to me like it's got at least one dead cylinder and a reciprocating assembly problem (the knock.) There are a couple of kinds of "knock":

- mechanical knock (bearing or piston clearance far too large)

and

- pre-ignition (mixture ignites too early) or detonation (explosion of end-gases in the combustion chamber). These are sometimes confused and lumped into a single term known as "spark knock."

Detonation usually occurs under heavy load when using lousy gas and/or a tune with too much timing. Pre-ignition occurs when hot metal or carbon particles ignite the mixture way before the plug is supposed to.

But it sounds like the knock you have is the mechanical variety.

Pull the plugs. Do a compression test on it. Keep in mind that if it's got a mechanical knock it's probably not worth doing even that since it's likely terminal... It might give you an idea as to which cylinder(s) might be involved.

 

[ddt4436]

Ok thanks alot for the info. I already had in mind to put another motor in but wanted some opinions before I preceded. Yeah you are absolutely right the guy did run nitro on it and it has 30lbs injectors on it. The car is performance red, charcoal grey interior, xpipe, new clutch, and 5speed. I only paid 2k for it and the guy was the original owner for 11 years came with all documentation, and original window sticker. lol Any way thank you as I am new to the 4.6 era.

 

[Dustys'99]

Look like a full build is in your near future. Gotta love the build threads, everybody gets to spend someone elses money